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Unformatted text preview: Statistic
Sample Mean p(1 Sample Proportion p)
of Statistic Statistic
sample means 2
n2 Special case when s1 s Difference of
sample proportions 1
n1 p1 (1 p1 )
n1 s2 1
n2 p2 (1 p2 )
n2 Special case when p1 p1 p 1
n2 observed expected
expected Chi-square test statistic -5- 2 2008 AP® STATISTICS FREE-RESPONSE QUESTIONS (Form B)
Spend about 65 minutes on this part of the exam.
Percent of Section II score—75
Directions: Show all your work. Indicate clearly the methods you use, because you will be graded on the
correctness of your methods as well as on the accuracy of your results and explanations.
1. A certain state’s education commissioner released a new report card for all the public schools in that state.
This report card provides a new tool for comparing schools across the state. One of the key measures that can be
computed from the report card is the student-to-teacher ratio, which is the number of students enrolled in a given
school divided by the number of teachers at that school.
The data below give the student-to-teacher ratio at the 10 schools with the...
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- Fall '11